GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you review the Exterior Lighting Systems Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

2

Verify that the stop lamps are always illuminated.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Disconnect the stop lamp switch.

Do the stop lamps remain illuminated?

Go to Step 5

Go to Step 4

4

Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Is the repair complete?

Go to Step 8

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5

Disconnect C205.

Do the stop lamps remain illuminated?

Go to Step 7

Go to Step 6

6

Repair the short to voltage in the tail lamp supply voltage circuit between the stop lamp switch and C205. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 8

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7

Repair the short to voltage in the tail lamp supply voltage circuit between the C205 and S304. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 8

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8

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3